Method of feeding solid carbonaceous material to a high temperature reaction zone

ABSTRACT

A method of feeding solid carbonaceous material to a gasifier operating under conditions of high temperature and pressure by forming a slurry of the carbonaceous material and a liquid vehicle, raising the internal pressure of the slurry to the operating level of the gasifier, drying the carbonaceous material by entraining the carbonaceous material in a hot gas stream, and thereafter separating the carbonaceous material and feeding the carbonaceous material to the gasifier. The method is adaptable to using the gasifier effluent to dry the carbonaceous material and includes using process materials such as char accumulated from the process and condensing steam to provide a portion of the source of carbonaceous materials and vehicle for the slurry.

United States Patent [1 1 Moody 1 Mar. 18, 1975 METHOD OF FEEDING SOLIDCARBONACEOUS MATERIAL TO A HIGH TEMPERATURE REACTION ZONE [75] Inventor:Burton E. Moody, Allentown, Pa.

[73] Assignee: Air Products and Chemicals, Inc.,

Allentown, Pa.

[22] Filed: Oct. 12, 1972 [21] Appl. No.: 296,959

[52] US. Cl 48/197 R, 48/210, 48/DlG. 7 [51] Int. Cl. C10j 3/06 [58]Field of Search..... 48/197 R, 202, 210, DIG. 7, 48/206; 34/12, 22, 33;110/7 R, 7 A, 7 S; 159/16 R, 29; 201/20; 252/373 STEAM HOT GASlFlEREFFLUENT 36 CARBONACEOUS MATERIAL CONDENSATE REACTANT STR EAM 3,715,1952/1973 Tassoney et a1. 48/197 R Primary ExaminerS. Leon BashoreAssistant ExaminerPeter F. Kratz Attorney, Agent, or Firm-James C.Simmons; Barry Moyerman [5 7 ABSTRACT A method of feeding solidcarbonaceous material to a gasifier operating under conditions of hightemperature and pressure by forming a slurry of the carbonaceousmaterial and a liquid vehicle, raising the internal pressure of theslurry to the operating level of the gas ifier, drying the carbonaceousmaterial by entraining the carbonaceous material in a hot gas stream,and thereafter separating the carbonaceous material and feeding thecarbonaceous material to the gasifier. The method is adaptable to usingthe gasifier effluent to dry the carbonaceous material and includesusing process materials such as char accumulated from the process andcondensing steam to provide a portion of the source of carbonaceousmaterials and vehicle for the slurry.

7 Claims, 2 Drawing Figures GAS TO PROCESS TO GASIFIER FEED NOZZLESMETHOD OF FEEDING SOLID CARBONACEOUS MATERIAL TO A HIGH TEMPERATUREREACTION ZONE BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention pertains to the feeding of solid carbonaceous material, e.g.coal, into a high-pressure, hightemperature reaction zone such as a coalgasifier. In coal gasification, finely pulverized coal is reacted in thepresence of steam and air oxygen at elevated temperature and pressure toform an effluent gas. If the product is to be a low BTU content gas, itis subject toremoval of hydrogen sulfide and then used directly. If ahigh methane content gas is to be produced, the effluent gas is thensubjected to various process steps including water shift reaction, acidgas removal and methanation thereby yielding a synthetic natural gas.figsuch process is discgasgd in U.S. Pat. No. 2,840,462; another is theprocess referred to as the; BCR Two-Stage Super-Pressure GasificationProcess developed by Bituminous Coal Research Incorporated ofMonroeville, PA; and a third pertains to generation fo a synthetic gasby electrothermal hydrogasification developed by the Institute of GasTechnology of Chicago, ILL.

In the above processes, the finely divided carbonaceous material (coal)is fed to the gasification vessel by a conventional lock hopper feedingsystem, a piston feeder, and a hydrocarbon liquid slurry respectivelyafter the coal has been ground to size, screened, dewatered, and storedin storage hoppers.

2. Prior Art.

Although use of a water slurry feed system for feeding solidcarbonaceous materials to a hydrogasification vessel has not been shownin the prior art, slurry feed systems for use with otherhigh-temperature reaction vessels for. finely divided solid carbonaceousmaterial is known. For example, U.S. Pat. No. 3,116,143 discloses aslurry feeding system wherein a coal slurry is injected directly intothe hot zone of a blast furnace for manufacturing iron. The Patenteediscloses injecting the slurry directly into the blast furnace withoutdewatering or otherwise removing the moisture.

Another feed system for feeding dried coal to a blast furnace as shownin U.S. Pat. No. 3,250,016 wherein the Patentee discloses a fluidizedbef for drying the coal by using blast furnace off gas prior toinjection into the blast furnace.

U.S. Pat. No. 3,207,102 discloses a slurry feed for a steam generatingunit such as is found in a commercial electrical generating plant. Hereagain the slurry is not dewatered prior to injection into the furnaceand the slurry is further comminuted by impingement against a breaker inthe furnace zone. U.S. Pat. No. 3,229,651 discloses an alternate slurryfeed means for conducting a finely divided solid carbonaceous materialinto a steam boiler or the like.

In a two-stage, super-pressure gasifier as developed by Bituminous CoalResearch Incorporated, it is contemplated that coal will be fed to thegasifier by a pressurized piston feeder in conjunction with a star-wheelfeeder. The coal will be pressurized by the piston feeder and fed intothe gasifier by the star-wheel feeder.

As an alternative system of feeding the gasifier, it has been suggestedto use-a lock hopper system with and without staged pressure letdownllnthe staged pressure system, a number of lock hoppers feed coal into ahighpressure surge vessel from which the coal would be fed to thegasifier. After the coal is transferred from a hopper into the surgevessel, the high-pressure gas in the hopper is vented to a series ofreceivers at different pressure levels down to atmospheric pressure. Gasis vented first to the highest pressure receiver and when pressureequalization is approached the venting is switched to the receiver atthe next lower pressure and so on until the final venting is toatmospheric pressure. The lock hopper is then refilled with coal thenpressurized in staged from each gas receiver in turn and the receiversare maintained at constant pressure by pumping gas from the receiver atthe next lowest pressure. F inal pressurization is made by pumping gasfrom the highest pressure receiver directly into the lock hopper.

In the non-staged lock hopper system, the coal is fed into oneof severalalternating hoppers, the hopperis pressurized, the coal is injected intothe gasifier and the hopper is vented for receiving the next charge.

In each of the above systems, the cost of compressing the gas increasessignificantly with increases in operating pressure. The staged systemwhile being more expensive to install operates at lower cost because ofa lower required volume of pressuring gas and lower compressing costs.

SUMMARY OF THE INVENTION In order to avoid the foregoing problems and toprovide an improved method of feeding solid carbonaceous material to ahigh-temperature, high-pressure reaction vessel, it has been discoveredthat the solid carbonaceous material can be dispersed in a liquidvehicle in the form of a slurry, the slurry can be raised to an elevatedpressure by means of a slurry pump, the slurry can be dried using thehigh-temperature effluents from the gasification vessel andsimultaneously entrained in a humidified gas, the solid carbonaceousmaterials can be separated from the gas into which it has beenentrained, and fed at high pressure into the gasifier by means of astream of hot recycled gas or stream. In addition, the separated gas canbe sent to the further purification steps without loss of volume ofproduction for the overall gasification process. It is furthercontemplated that char separated and collected in the gasificationprocess and condensed steam from the process or boiler feed water can beused in making up the initial slurry.

Therefore, it is the primary object of this invention to provide animproved method for feeding solid carbonaceous material to ahigh-pressure, high-temperature reaction zone.

It is another object of this invention to provide a method for feedingsolid carbonaceous material to a gasification vessel.

It is still another object of this invention to provide a method forfeeding pulverized coal to a gasification vessel.

It is yet another object of this invention to provide a method forfeeding solid carbonaceous material to a partial oxidation reactor.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic drawing of themethod of the instant invention.

FIG. 2 is a schematic drawing of the method of the instant invention asapplied to a process for producing a synthesis gas.

DETAILED DESCRIPTION OF THE INVENTION so that the end product is a gassubstantially methane that is suitable for pipeline use.

Referring now to FIG. 1, there is shown a slurry tank with an impeller12 mounted on shaft 14 rotated by a suitable motor or other rotatingdevice not shown. The tank 10 receives the pulverized carbonaceousmaterial from a feed hopper or pipe that is shown by arrow 16. Thepulverized carbonaceous material generally is coal but can include coke,char or low grade volatile materials such as lignite. Arrow l8designates a source of supply of water which can be fresh water fromutility, boiler feed water, or condensed steam from the processgenerally referred to as condensate. The slurry tank 10 isconnected viaconduit 10 to a slurry pump 22 which in turn is connected throughconduits 24, 26, heat exchanger 28, and valve 30, to a mixing chamber32. The heat exchanger 28 is included in the process stream and can bebypassed if not needed as by conduit 34. If used, the heat exchanger 28can be used to heat the slurry by means of heat exchange with steam, hotcondensate, hot gas from the gasifier or hog gas from an independent gasheater (not shown). The mixing chamber 32 contains an inlet conduit 36for receiving hot gas, which in turn is connected to another conduit 38having disposed therein temperature indicating control valve 40. Anoutlet conduit 42 is connected to a separator 44, which in turn has anoutlet gas conduit 46 and a solids removal device shown as 48. Removaldevice 48 in turn is connected to a coal feeder 50, which in turn isconnected to a conduit 52 to a venturi nozzle 54. A conduit 56 isconnected to the venturi nozzle 54 in order to entrain the coal into areactant gas for injection of the reactant and gas and coal into thegasifier.

In the above process shceme, solid carbonaceous material, e.g. coal isfed through conduit 16 and condensate through conduit 18 into the slurrytank 10. The impeller 12 is used to agitate the coal and condensate intank 10 to form a slurry having approximately 50 percent by weightsolids. The slurry is then pumped under pressure to the mixing chamber32 which chamber is maintained at the pressure of the gasifier vessel asthe slurry is sprayed therein. In the mixing chamber 32, the slurry iscontacted by the hot gasifier effluent entering through conduit 36. Theaction of the hot gasifier effluent and the spraying of the slurrycauses the water to v be driven off and the solid carbonaceous material(coalibecomes dried and entrained in the humidified hot gasifiereffluent: The evaporated water humidifies the effluent gas to enhancesubsequent reactions in the shift convertor where the gas is used. Steamconduit 38 is included to maintain the temperature of the spray dryingchamber and to adjust the humidity of the effluent gas with theentrained solid carbonaceous material which is passed through conduit 42to a cyclone separator and solid carbonaceous storage vessel 44 whereinthe solid carbonaceous material is separated from the gas ans stored foruse as needed with the solid carbonaceous material being withdrawnthrough a solids removal device, e.g., conduit 48, into feeder 50 forfeeding into the gasification vessel. The dried carbonaceous material isfed under pressure from conduit 52 into centuri feed nozzle 54 forpneumatic feeding to the reactor or gasifier. It may be advantageous toentrain the coal in a reactnat stream 56 which can be either hotrecycled gas or steam used in the gasifier reaction vessel as in U.S.Pat. No. 2,840,462. Alternatively, the coal can be fed through conduit52 directly to the gasifier nozzles. The gas separated in separator 44is conducted through conduit 46 to subsequent processing steps (e.g.water gas shift reactor, acid gas removal, and methanation) in theoverall gasification scheme so that none of the gasifier effluent issacrificed in feeding the coal or other solid carbonaceous material tothe gasifier.

The foregoing process provides a method for feeding dried preheated coalto a gasifier. It is possible to preheat the coal during drying to atemperature .of approximately 500F therebyachieving overall processeconomies in the production of synthetic natural gas by reducing oxygenrequirements.

The foregoing basic method can be modified for application to othergasification schemes. For example. there is a proposed coal gasificationprocess developed by Bituminous Coal Research Incorporated wherein asynthetic natural gas will be produced at the rate of 250 MM SCF/SD. Thegasification vessel for such a process requires heated coal at 80atmospheres pressure for gasifier feed and requires process gasifiereffluent temperature of 660F with a 1:1 steam to dry gas ratio for feedto the shift converter, which is the step after the gasifier.

For such a gasification vessel, the coal slurry is prepared as a 50percent by weight mixture by adding coal at approximately 60F, hotcondensate at approximately 212F and a low pressure steam at 50 psig and298F into the slurry tank 10. The slurry is pumped at the desiredpressure (80 atmospheres) and preheated by hot condensate in heatexchanger 28. Finally, the slurry is dried (32) and the coal and processgas separated in the cyclone 44. In order to accomplish this, it isproposed that the overall system will appear as follows. The firstsection of the process will encompass multiple train slurry preparationconsisting of makedown tanks and mixers, low-pressure, centrifigalslurry pumps, holding tansk with mixers, and circulation pumps. In thissection, coal sized at approximately percent less than 200 mesh and hotcondensate direct from deaerators will be combined to produce a 50weight percent coal water slurry in the make-down tanks. Each tank willhave a 10-minute residence time and be of 16,500 gallon capacity. Theslurry mixer will employ an axial flow, constant velocity dischargeimpeller with the shaft and impeller covered with rubber to minimizeerosion. There will be provision in these tanks for steam sparging forheating of the slurry and usual circumstances where the coal may havesettled to the bottom of the tank. After the slurry is throughly mixed,it will flow into a manifold from which it will be pumped to the holdingtanks. Low pressure centrifugal pumps each rated at 50 percent of plantcapacity will be used to pump the slurry into the holding tanks whichwill each have a capacity of approximately 65,000 gallons and willprovide 40-minute residence time for the slurry. As with the make-downtanks, the mixers will require protection from erosion; however, thehorse power needed will be less since they will only be required toagitate the slurry enough to maintain the coal in the form of a slurry.Circulating pumps will be provided to circulate the slurry through amanifold and return it to the pressurized slurry tanks in order tomaintain the stability of the slurry.

The next section of the process containsof the slurry pumping and hotcondensate heat exchangers. The slurry pumps will develop the systempressure of approximately 80 atmospheres using reciprocatingsingleacting Triplex plunger pumps. The slurry will be discharged fromthe pumps at 1,200 psi and approximately 230F into a heat exchangerwherein the slurry will be raised to approximately 430F before feedinginto the dryer. The temperature of 430F is required in order to obtainthe desired gas and coal temperature with a 1 to 1 steam to dry gasratio in the process gas from the dryer. Care must be taken inconstructing special inlet channels and distribution in the heatexchanger to prevent or minimize erosion due to the abrasivecharacteristics of the slurry.

The next section of the overall process will consist of slurry dryingwherein there is employed a spray dryer, a cyclone, and a pair of coalreceivers. The coal slurry is dried and the water is vaporized in aspray dryer which will operate at approximately 80 atmospheres pressurewith exit gas temperatures of 660F. Gas used for heating the slurry willbe effluent gas from the gasifier. In the BCR Process, the effluent gasfrom the gasifier is at a temperature of 1,750F but before being used issubjected to a char separation in a cyclone separator. The char is thenrecycled to the gasifier. In the BCR Process, a second cycloneseparation is effected to eliminate the balance of the char from thegaas and lower the gas temperature to approximately 1,100F. A portion ofthe gas from the first and second cyclone is combined with a nettemperature of about 1,600F which gas is used in the spray dryers tocontent the slurry which is pumped into the dryer and atomized. Ifrequired, steam canbe added'to increase the atomization of the slurry orit can be added later to achieve the desired steam to dry gas ratio. Thedried coal and humidified gas is then taken over into a cyclone wherethe coal is separated and conducted into a pair of receivers, which willoperate on a switching cycle to eliminate back surging through thecyclone. The separated gas will be taken and fed to the carbon monoxideshift converters for further processing into the required pipeline gas.At this stage, the coal can be withdrawn from the storage hoppers underpressure and fed to the gasifier for reacting.

There is shown in FIG. 2 a method of using a slurry feed in conjunctionwith a commercial partial oxidation unit. The partial oxidation unit isshown in U.S. Pat. No. 2,595,234 and is used to produce a synthesis gasconsisting mainly of water vapor, hydrogen, carbon dito free the mixerand impeller for start up under u'n- I oxide, and carbon monoxide, whichcan be subsequently shift converted to carbon dioxide and hydrogen. Thehydrogen is then separatedout and used for various processesincludinggasification of crude oil or as product hydrogen for other manufacturingoperations.

The partial oxidation reactoris shown as60 in FIG. 2 and has an inletconduit 62 for receiving the solid carbonaceous material to be reacted,a second inlet conduit 64 for receiving oxygen that reacts with thesolid carbonaceous material and outlet conduit 66 for conduiting thesynthesis gas out of the reactor and a bottom clean out 68 for removingslag and/or ash from the gasifier. The product gas is conducted fromconduit 66 to a separator 70 and from separator 70 through conduit 72 toa waste heat boiler 74, from waste heat boiler 74 through conduit 76 toa dryer 78, from dryer 78 to separator 80 and from separator 80 throughto purification (shift) through conduit 81. Coal is fed to the reactor60 through conduit 82 which is in turn connected to a pneumaticinjectionm device 84 which receives the coal feed from conduit 86 andcarries the coal into the reactor 60 by means of steam shown by arrow88. Conduit 86 is connected in turn in reverse order to separator 80 anddryer 78. From dryer 78 a conduit 90 is connected to preheater 92 whichin turn is connected to slurry pump 94 through conduit 95-for receivingthe coal slurry. Slurry pump 94 is connected to the slurry tank 96 byconduit 98. Slurry tank 96 include'san impeller 100 and a drive shaft102, which are connected to a suitable source of power such as a motor(not shown). Alternatively, the slurry can be made as the result of wetgrinding of the carbonaceous material in which event tank 96 is bypassedthrough conduit 104 directly to the slurry pump 94. y

In operating the method of FIG. 2 in the one alternative solidcarbonaceous material in the form of coal, char, coke, or combinationsthereof are introduced into the slurry tank 96 and are designated asarrow 106. Condensate is added to tank 96 as indicated by arrow 108,e.g., condensate from the process in the form of boiler feed water,condensed steam, or fresh water. The impeller is activated to providethe proper mixing of the solid carbonaceous material and condensate toform the slurry. Alternatively as shown by arrow 104, the slurry can beformed as the coal is wet ground to size and passed directly to theslurry pump 94 through conduit 104. The preferably slurry is one thatconsists of 40 to 60 percent by weight water with the rest solidcarbonaceous material. The slurry is passed to the slurry pump 94 whereits pressure is raised to that above the operating pressure of thegasifier 60 and is then preheated in heat exchanger 92 if the overallheat balance of the system requires additional heat into the system. Theslurry is then injected into the dryer 78 where it is contacted by thehot effluent from the waste heat boiler 74 and the water is driven offand the solid carbonaceous material is raised in temperature andentrained in a gas. As described in connection with FIG. 1, a source ofsteam can be provided through conduit 77 to control the humidity andtemperature of the effluent in conduit 79 from dryer 78. The gas solidmixture is then conducted to the cyclone separator 80 wherein the coaland gas are separated, the gas going from conduit 81 on to furtherpurification and the coal being conducted through conduit 86 into thegasification vessel by means of the injection nozzle 84. Waste heatboiler 74 is included in'this system to recover heat and-at the sametime-to produce high-pressure steam for the overall reaction and forinjecting into the gasifier itself.

The foregoing method of feeding a partial oxidation unit accomplishesthe following:

1. The process provides a dry preheated carbonaceous solid fuel to thegasifier thereby increasing gasifier efficiency.-.

2. In the drying preheating step, the water is evaporated without theuse of additional oxygen and simultaneously provides steam required forsubsequent shift operations of the effluent.

3. The process provides a method for utilizing a high-.

sulfur fuel such as coal, petroleum, coke or the like by producingsulfur as hydrogen sulfide because of the overall reducing atmosphere.

Having thus described my invention, what is desired to be secured byLetters Patent of the United States is contained in the followingclaims.

I claim: 1. A method of feeding carbonaceous particles to agasifier-operating at elevated temperature and pressure comprising thesteps of:

forming a slurry of solid carbonaceous particles with water as a liquidvehicle; pumping the slurry into a drying chamber, said drying chamberbeing separated from said gasifier, maintained at approximately theoperating pressure of the gasifier wherein the slurry is mixed with hoteffluent gases from the gasifier so that the carbonaceous particleswithout substantial reaction are dried and heated and entrained in theeffluent gas;

substantially immediately separating the entrained carbonaceousparticles from the effluent gas which effluent gas includes evaporatedwater vehicle in the form of steam; and injecting the separatedcarbonaceous particles into the gasifier.

2. A method according to claim 1 wherein the slurry I is preheated byindirect heat exchange with a hot gas prior to entering the dryingchamber.

3. A method. according to claim 1 wherein steam is added to the dryingchambercontaining the slurry and gasifier effluent gas to adjust'thetemperature of the effluent gas thereby controlling the humidity oftheeffluent gas.

4. A method of feeding solid carbonaceous particles to a gasifieroperating at high temperature and high pressure comprising the steps of:

providing a feed stream of solid carbonaceous particles suspended inwater; g

raising the internal pressure of the feed stream to a pressure above theoperating pressure of the gasifier;

introducing-the pressurized feed stream to a drying chamber, said dryingchamber being separated from said gasifier, wherein it is contacted byhot gaseous effluent from the gasifier without substantial reaction sothat, the water is evaporated, and the dried solid carbonaceousparticles are entrained in the gaseous effluent;

substantially immediately separating the dried solid carbonaceousparticles from the gaseous effluent; and entraining the separated solidcarbonaceous particles in a stream of reactant being fed into thegasifier.

5. A method according to claim 4 wherein the feed stream is a slurry of40% by weight solid carbonaceous particles selected from the groupconsisting of. coal, coke, char or mixtures thereof in water prepared ina mixing tank.

6. A method according to claim 4 wherein the slurry is preheated priorto being introduced into the drying chamber.

7. A method according to claim 4 wherein the gaseous effluent separatedfrom the solid carbonaceous particles consists "essentially of-watervapor, carbon monoxide, and hydrogen, and issubjected to a subsequentshift step wherein carbon dioxide and hydrogen .LILAUAJU ILLA la. .1 M

mm: r I est-141cm; OF contraction Patent 3,871,839 Dated March 18 1975Inventoflx) Burton E. Moody It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 26, "f0" shouldbe -of- 0 I Column 1, line 48, "bef"should be--bed-- Column 2, line 15, "staged" should be--stages Colunm 3,line 34, after "conduit" "10" should be-20- Column 3, line 41, meg"should be-hot- Column 3, line 54, shceme" should bescheme Column 4 line10, "ans" should beand-- Column 4, 1ine 15, "centuri" shouldbe-venturi-- Column 4, line 17, "reactnat" should be-re a ct ant- Column4, line 57, after "down" de1etequotation marks-- Column 4, line 58,"tansk" should be--tanks Column 5, line 18, "contains" shouldbe--consists- Column 5, line 45, "gaas" should begas-- Column 5, line49, "content" 514511161 be-contact-- Column 6, lines 11-12,"con-duiting" should beconducting nmmv' frn .I QMMMQE conmewon PatentNo. 3,871,839 Dated March 18 1975 .Invent fls) Burton E. Moodv(CONTINUED) It is certified that error appears in the above-identifiedpatent and that said Letters Patent: are hereby corrected as shownbelow:

m I Page 2 of 2 4 r O I v Column 6 line 2]., after "injection" d elet e'm Column '6, line 48, "preferably" should be-preferable- Q Column 7,lines 34-35,; after "entrained" and before "carbonaceous" insert-driedSigned and Scaled this second Day of December 1975 [SEAL] Attest:

. RUTH c. MASON c. MARSHALL mum Arresting Officer Commissioner ofParemsand Trldenlarks in m UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION PatentNo 3,871,839 Dated March 18, 1975 Burton E. MoodyInventor(s) It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 47, "stream" should read steam Column 5, line 3,"throughly" should read thoroughly Signed and Scaled this sixth D y ofJanuary 1976 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (mnmissioner nfPatentsand Trademarks

1. A METHOD OF FEEDING CARBONACEOUS PARTICLES TO A GASIFIER OPERATING ATELEVATED TEMPERATURE AND PRESSURE COMPRISING THE STEPS OF: FORMING ASLURRY OF SOLID CARBONACEOUS PARTICLES WITH WATER AS A LIQUID VEHICLE;PUMPING THE SLURRY INTO A DRYING CHAMBER, SAID DRYING CHAMBER BEINGSEPARATED FROM SAID GASIFIER, MAINTAINED AT APPROXIMATELY THE OPERATINGPRESSURE OF THE GASIFIER WHEREIN THE SLURRY IS MIXED WITH HOT EFFLUENTGASES FROM THE GASIFIER SO THAT THE CARBONACEOUS PARTICLES WITHOUTSUBSTANTIAL REACTION ARE DRIED AND HEATED AND ENTRAINED IN THE EFFLUENTGAS;
 2. A method according to claim 1 wherein the slurry is preheated byindirect heat exchange with a hot gas prior to entering the dryingchamber.
 3. A method according to claim 1 wherein steam is added to thedrying chamber containing the slurry and gasifier effluent gas to adjustthe temperature of the effluent gas thereby controlling the humidity ofthe effluent gas.
 4. A method of feeding solid carbonaceous particles toa gasifier operating at high temperature and high pressure comprisingthe steps of: providing a feed stream of solid carbonaceous particlessuspended in water; raising the internal pressure of the feed stream toa pressure above the operating pressure of the gasifier; introducing thepressurized feed stream to a drying chamber, said drying chamber beingseparated from said gasifier, wherein it is contacted by hot gaseouseffluent from the gasifier without substantial reaction so that, thewater is evaporated, and the dried solid carbonaceous particles areentrained in the gaseous effluent; substantially immediately separatingthe dried solid carbonaceous particles from the gaseous effluent; andentraining the separated solid carbonaceous particles in a stream ofreactant being fed into the gasifier.
 5. A method according to claim 4wherein the feed stream is a slurry of 40% by weight solid carbonaceousparticles selected from the group consisting of coal, coke, char ormixtures thereof in water prepared in a mixing tank.
 6. A methodaccording to claim 4 wherein the slurry is preheated prior to beingintroduced into the drying chamber.
 7. A method according to claim 4wherein the gaseous effluent separated from the solid carbonaceousparticles consists essentially of water vapor, carbon monoxide, andhydrogen, and is subjected to a subsequent shift step wherein carbondioxide and hydrogen are produced.